The present invention relates to the coding and decoding of structured documents based on XML, such as are provided for by MPEG-7, for example. XML (extensible markup language) is a standard for the definition of document structures. It is used for representing structured data in a text file and forms the basis for the language XHTML, for example. Such documents structured on an XML basis are based on a set of structured elements, also referred to in the following as a “schema”, such as can be specified using, for example, a document type definition (DTD), an XML schema, or multi-media description schemes (DS).
A draft paper from the ISO/IEC, namely CD 15938-1 Information Technology—Multimedia Content Description Interface: Systems, ISO/IEC JTC 1 SC29/WG111/N3701, La Baule (France), October 2000, in particular on pages 15 to 22, discloses the binary format of MPEG-7 files and the structure of navigation paths using tree branch code tables.
The present invention is concerned with the optimization of the coding of structured XML documents. An object of the present invention is, thus, to specify methods for improving the functionality of the binary representations of XML-based content descriptions, particularly for MPEG-7 documents, using which the data set to be transmitted will be as small as possible, search operations within the document will be as simple as possible, and any extensions to an instanced document which are not contained in the schema template can be effected with the least possible effort.